Method and device for treating objects by means of a liquid

ABSTRACT

The invention, in a specific embodiment, relates to a method and to a device for treating substrates ( 29 ) in printed circuit industry by means of a liquid. The invention is characterized in that the substrates ( 29 ), on their surface, are provided with a layer that is partially removed under the influence of the liquid while a pattern is formed. A plurality of nozzles ( 24 ) are provided for discharging the liquid and are linked with at least one liquid connection ( 12 ). Said liquid connection ( 12 ) is linked with a liquid reservoir and can be opened and closed. A valve ( 17 ) is provided directly on every nozzle ( 24 ), said valves ( 17 ) being individually controlled to open and close. The objects ( 29 ) are displaced along a track of movement (B) relative to the nozzles ( 24 ). A specific amount of liquid is discharged by opening and closing the valves ( 17 ) or the liquid connections ( 12 ) and has a certain distribution across the surface ( 26 ).

FIELD OF APPLICATION AND STATE OF THE ART

The invention relates to a method and a device for treating objects suchas, for example, substrates in the printed circuit board industry, bymeans of a liquid.

As a rule, objects, substrates or so-called printed circuit boards havea layer, for example a layer of conductive material like copper, ontheir surface. This layer can be removed under the influence of aliquid, which can be in particular an etching medium, in order to form apattern in the layer. The liquid is discharged by means of nozzles,which are connected to a liquid connection.

A problem exists in that often such nozzles are provided as a type of afield of nozzles in larger numbers, side-by-side, and also one behindthe other. The substrates are layed flat and moved under this field ofnozzles and are thereby sprayed with the liquid. The problem arisesherein that basically a full, even distribution of liquid is applied tothe substrates. However, the liquid can easily flow off towards the edgein the outer areas of the substrate. As such, the liquid exchange isgreater in the outer areas of the substrate as significantly more freshetching liquid is applied. In contrast, a sort of liquid accumulation(so-called puddle effect) is formed in the center area of the substrate,and as such, the exchange of liquid is by far less. This has the resultthat significantly more of the layer is etched away in the outer areasthan in the center area, and thus the result is not as good or asubstrate may possibly become nonusable.

To overcome this problem it is known from the DE 33 45 125 to apply lessliquid in the outer areas of the substrate or to reduce the through-flowof liquid. Control valves and flowmeters are, for this purpose, providedin the supply pipes to the nozzles. This device is very expensivebecause of the flowmeters needed for this. Also, controlling the valvesis not easy, as complicated valves are needed.

PURPOSE AND SOLUTION

The basic purpose of the invention is to provide an above-identifiedmethod and a device, with which the application of liquid onto suchobjects is individually and intentionally possible. The inventive methodand the device are thereby kept as simple as possible.

This purpose is attained by a method having the characteristics of Claim1 and a device with the characteristics of Claim 10. Advantageous andpreferred embodiments of the invention are the subject matter of furtherclaims and will be discussed in greater detail hereinafter. The wordingof the claims is made part of the content of the application viaexpressed reference.

A liquid connection for the nozzles is in the inventive method connectedto a liquid reservoir and can be opened and closed. A valve is directlyassociated with each nozzle at as small a distance as possible from thenozzle. An extremely delay-free control of the liquid application by thenozzle is advantageously made possible in this manner. The valves arethereby individually controlled for opening or closing. The valves,however, can also be simultaneously controlled in groups. Thus anindividually desired liquid application or a thus formedliquid-discharge picture is possible.

The substrates or objects are moved, advantageously with a continuousspeed, along a path of movement relative to the nozzles. By opening andclosing the valves it is possible, on the one hand, to create with theliquid connection being open a specific liquid discharge with apredetermined surface distribution over the path of movement. As analternative, it is possible to additionally open or close the liquidconnections in order to achieve this surface distribution.

The liquid connections are for this purpose are advantageously designedto be elongated and have several nozzles which are spaced at a specificdistance from one another. The liquid connections can be opened andclosed preferably via a lock. Several of such liquid connections are, ina preferred embodiment, arranged parallel to one another and one behindthe other. They can in this manner cover a surface of an object beingpassed along the path of movement. The liquid connections areparticularly and preferably individually controlled to open or close,depending on the predetermined surface distribution of the liquiddischarge desired.

The liquid connections are advantageously stationary and the objectsmove on a path of movement. This path of movement can be a transportpath, for example a roller path or the like. Liquid connections arepreferably provided at least above the path of movement of the objectsand bring the liquid from above onto the objects.

One possibility of an embodiment of the invention provides, in order toachieve the surface distribution, that the valves of the nozzles areexclusively controlled. Thus a control of the process can be limited tothe valves of the nozzles. Another possibility of an embodiment of theinvention provides that the nozzles of the valves and also the locks ofthe liquid connections are opened and closed in order to achieve thesurface distribution. The nozzles are thereby in a first steppreadjusted to be opened or closed by means of the valves. The liquidconnections or their locks are then, during the process itself, openedand closed. Thus the liquid distribution is preadjusted in a way throughthe valves of the nozzles, and the discharge of liquid itself is thenactivated by means of opening and closing the connections. The valvescan in this manner be preserved as they do not have to be continuouslyoperated or adjusted. Since one liquid connection carries a plurality ofnozzles, it is easier to cycle the discharge of liquid through thisliquid connection.

Less liquid is applied in the outer areas of a substrate (i.e., to thelateral and/or the front and rear outer areas of the substrates) than ina center area in the inventive method in order to avoid the applicationof too much liquid. The application of liquid can thereby basically bereduced as desired. It is preferred that an amount of applied liquid isless, which occurs particularly preferred through a time reduction. Thismeans that the flow of liquid through a nozzle, if such flow occurs atall, is the same in every case. The respective nozzles are, however,more often or for a longer time period switched off or more seldomactivated in the respective outer areas.

The nozzles are advantageously stationarily arranged. The nozzles areaccording to one possibility of the invention designed rigidly and witha fixed discharge direction. The nozzles can according to another, morecomplicated possibility be moved or changed in their alignment. This canbe done for each nozzle individually or in groups. The change of thealignment can occur both in one direction or plane, in several planes,or entirely freely selectable. It is possible through the provision ofdrives to control the alignment of the nozzles by, for example,electromotorically. Such groups of nozzles can be divided according toliquid connections, for example, together with the liquid connection inthe form of a pipe or the like. A yet finer and arbitrarily achievabledischarge of liquid can be achieved with nozzles adjustable in thismanner.

One possibility of an embodiment of the invention provides that, viewedin the direction of passage of the objects, only one or few nozzlesdischarge liquid in the front area. Increasingly more nozzles dischargeliquid in the direction of passage, which nozzles thus advantageouslycover a larger surface or have a greater expansion. Thus it is possibleto produce a surface distribution which is wedge-shaped and widens inthe direction of passage. It is furthermore possible to permit, in aninventive method, for several objects to pass through side-by-side. Itis hereby possible to produce for every object a specific profile, suchas, for example, a wedge-shaped profile. It is also possible to producea separate and/or different profile for each object.

One possibility for operating valves of nozzles is by means ofcompressed air. This is relatively simple and yet reliable and requiresvery little service. Compressed-air pipes can be guided directly to thevalves.

These and further characteristics can be taken, besides from the claims,also from the description and the drawings, whereby the individualcharacteristics each by themselves, or several together in the form ofsub-combinations, are realized in one embodiment of the invention and inother areas, and can represent advantageous and by itself protectableembodiments, for which protection is here claimed. The division of theapplication into individual sections and in-between titles does notlimit the statements made under these titles in their universalvalidity.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are schematically illustrated inthe drawings and will be described in greater detail hereinafter. In thedrawings:

FIG. 1 is a lateral cross-sectional view of an inventive nozzle tubewith a plurality of discharge systems with nozzles arranged on thenozzle tube;

FIG. 2 is an enlarged cross-sectional view of one of the dischargesystems depicted in FIG. 1;

FIG. 3 is a further cross-sectional view of the discharge system of FIG.2 with the nozzle; and

FIGS. 4 to 6 are various schematic illustrations of nozzle fields withdistribution profiles and printed circuit boards of varying formats.

DETAILED DESCRIPTION AND EXEMPLARY EMBODIMENTS

FIG. 1 shows in a lateral view an inventive device 11 with a nozzle tube12. The nozzle tube 12 has liquid inlets 13 on the left and on the rightwhich extend through the nozzle tube 12. The nozzle tube 12 can beopened and closed by locks schematically illustrated in FIG. 4. Thelocks 27 of the nozzle tubes 12 can be pneumatically operated.

The nozzle tube 12 carries a plurality of discharge systems 15, whichare equally spaced from one another and are identically designed. Thedischarge systems 15 connect to the nozzle tube 12 by means of aconnecting piece 16 which allows for the conduction of liquid betweenthe nozzle tube 12 and discharge systems 15.

Each of the discharge systems 15 include a valve system 17 controlled bya compressed-air connection 18. The discharge systems 15 can, in otherembodiments, be arranged at varying intervals on the nozzle tube 12. Itis also possible to provide discharge systems of different designs,and/or connect discharge systems to both sides of the nozzle tube 12.

FIG. 2 illustrates an individual discharge system 15 on the nozzle tube12 according to the illustration of FIG. 1. A compressed-air pipe 19extends into a compressed-air connection 18. The opposite end of thecompressed-air pipe 19 is connected to a compressed-air system (notillustrated). Each compressed-air pipe 19 can be individuallycontrolled. Consequently, each discharge system 15 can be individuallycontrolled through its corresponding compressed-air pipe 19.

The liquid-conducting connection to the nozzle tube 12 occurs through aliquid channel 21 contained within or attached to connecting piece 16.The liquid channel 21 extends through a valve system 17, wherein adiaphragm valve is opened and closed by means of the compressed-airconnection 18. This diaphragm valve does not need to be discussed ingreater detail at this time. The liquid channel 21 ends in a nozzleinlet 22, which, in FIG. 2, extends into the drawing plane.

FIGS. 2 and 3 shows on the one hand that the discharge system 15, orrather the nozzle 24, is arranged very close to the nozzle tube 12. Onthe other hand, one can see that the valve system 17, and thus theinfluence on whether the nozzle 24 operates, is provided directly on thenozzle. Thus a very precise and up-to-date influence of the nozzle ispossible.

FIG. 3 shows how the nozzle 24 is arranged below the valve system 17.The nozzle 24 connects to the liquid channel 21, and thus to the nozzletube 12, by the nozzle inlet 22. The precise design of the nozzle 24does not need to be discussed here since it can be seen in FIG. 3 andcorresponds essentially to conventional nozzle systems.

A nozzle jet extends downwardly from the nozzle 24. The nozzle jet canbe adjusted regarding its profile or its width on the nozzle 24 itself.This can be done by a manual or automatic control.

FIG. 4 illustrates schematically a nozzle field 25. The field comprisesa plurality of discharge systems 15. These are arranged side-by-side onthe nozzle tube 12 corresponding to FIG. 1. The conduction of liquidthrough these nozzle tubes, which are not illustrated in FIG. 4, can becontrolled by means of locks 27.

It can be recognized that some of the discharge systems 15 are crossedout. This means that they are blocked by means of the valve systems 17during operation and do not cause the discharge of liquid. Thus adistribution profile 26 a results from the active discharge systems 15,which distribution profile 26 a is made clear by the dashed line. As canbe taken from this, the distribution profile 26 a in FIG. 4 iswedge-shaped.

One printed circuit board 29 a moves through the nozzle field 25 indirection B. The discharge of liquid onto the printed circuit board 29 ais specified by the distribution profile 26 a. From this one canrecognize that the discharge of liquid is stronger in a central area ofthe printed circuit board 29 a or a center strip than towards the edgesince here more nozzles are activated.

Liquid is discharged in such a manner that the discharge systems 15 arepreadjusted by the valve systems 17 so as to be opened or closed tocorrespond to the distribution profile 26 a. The discharge systems 15are then controlled by means of the locks 27 through the nozzle tubes12. As has been discussed above, the valve systems 17 are thus protectedas they do not have to be operated as often.

FIG. 5 again illustrates the nozzle field 26 of FIG. 4. Since theprinted circuit board 29 b has here a smaller width, the wedge-shapeddistribution profile 26 b is designed to be more tapered or adjusted toits width. The printed circuit board 29 b is here furthermore shifted tothe right relative to the center axis of the nozzle field 25. For thisreason, the distribution profile 26 is also shifted to the right.

In order to make an adjustment to a printed circuit board that isshorter in the direction of movement B, it is possible to turn offentire rows of discharge systems 15, or nozzle tubes 12, which extendperpendicularly with respect to the direction of movement B.

FIG. 6 also illustrates the nozzle field 25 of FIG. 4. Here twoside-by-side printed circuit boards 29 c and 29 d are to be applied withliquid. From this results the distribution profile 26 c or 26 d, whichagain is illustrated by dashed lines. As before, these distributionprofiles are directed wedge-shaped against the path of movement B. Thetwo distribution profiles 26 c and 26 d overlap in the upper center areaof the discharge systems 15. This, however, does not create any problemswhatsoever in practice.

If the two printed circuit boards 29 c and 29 d were moved in directionof movement B separate from one another, then the distribution profiles26 would actually be the same. Merely the timely use of each profile 26would vary and would be adjusted individually for each printed circuitboard.

The Figures do not show a unit for controlling the discharge of theliquid. However, it is envisioned that such a control unit can have, inparticular, a sensory mechanism which detects position, alignment andsize of the printed circuit boards and, adjusted thereto, determines thedischarge of liquid, or a corresponding distribution profile used in thedischarge of liquid.

1. A method for treating objects, in particular substrates (29) in theprinted circuit board industry, by means of a liquid, characterized by:the objects (29) have a layer on their surface, which layer is partiallyremoved under the influence of the liquid while a pattern is formed,several nozzles (24) are provided for discharging the liquid and areconnected to at least one liquid connection (12), the liquid connection(12) is connected to a liquid reservoir and can be opened and closed, avalve (17) is provided directly on every nozzle (24), the valves (17)can be controlled individually for opening or closing, the objects (29)are moved along a path of movement (B) relative to the nozzles (24), aspecific amount of liquid is discharged with a surface distribution(26), which is predetermined or can be predetermined over a path ofmovement, by means of opening and closing the valves (17) and/or theliquid connections (12).
 2. The method according to claim 1,characterized in that the liquid connections (12) are elongated, haveseveral nozzles (24) spaced from one another, and can be opened andclosed each through a lock (27), whereby several liquid connections (12)are arranged parallel to one another and one behind the other in orderto cover a surface above the path of movement (B) and can in particularbe individually controlled.
 3. The method according to claim 1,characterized in that the liquid connections (12) are arranged onebehind the other relative to the path of movement (B), and the objects(29) are moved along the path of movement (B).
 4. The method accordingto claim 1, characterized in that for achieving a specific surfacedistribution (26) of the liquid discharge over the path of movement (B)the valves (17) of the nozzles (24) are controlled.
 5. The methodaccording to claim 4, characterized in that for achieving the surfacedistribution (26) the valves (17) of the nozzles (24) are exclusivelycontrolled.
 6. The method according to claim 1, characterized in thatfor achieving the surface distribution (26) in the passage of theobjects (29) the nozzles (24) are preadjusted by means of the valves(17) in a first step, and the liquid connections (12) are opened andclosed for cycling in a second step.
 7. The method according to claim 1,characterized in that for achieving a specific surface distribution (26)of the liquid discharge less liquid is applied to the lateral and/orfront and rear outer areas of the objects (29) than in the center area,whereby the liquid discharge is preferably less in amount and time. 8.The method according to claim 1, characterized in that the nozzles (24)are moved or changed in their alignment, whereby the nozzles (24) arepreferably changed individually or in groups, and in particular thegroups are divided in accordance with liquid connections (12).
 9. Themethod according to claim 1, characterized in that in direction ofpassage of the objects (29) along the path of movement (B) of the frontnozzles (24) only one or few nozzles discharge liquid and in directionof passage increasingly more nozzles, preferably with coverage of alarger surface, discharge liquid.
 10. A device for treating of objects,in particular substrates (29) in the printed circuit board industry, bymeans of a liquid, in particular for carrying out the method accordingto one of the preceding claims, characterized by: the objects (29) havea layer on their surface, which layer is partially removed under theinfluence of the liquid while a pattern is formed, several nozzles (24)are provided for discharging the liquid and are connected to at leastone liquid connection (12), the liquid connection (12) is connected to aliquid reservoir and can be opened and closed, a valve (17) is provideddirectly on every nozzle (24), the valves (17) can be controlledindividually for opening or closing, the objects (29) are moved along apath of movement (B) relative to the nozzles (24), the valves (17)and/or the liquid connection (12) can be opened and closed in order toproduce a specific liquid discharge with a surface distribution (26)predetermined through a path of movement (B).
 11. The device accordingto claim 10, characterized in that the liquid connection (12) iselongated, has several nozzles (24) spaced from one another and can beopened and closed through a lock (27), whereby preferably several liquidconnections (12) are arranged parallel to one another and one behind theother for covering a surface above the path of movement (B) and can inparticularly be individually controlled.
 12. The device according toclaim 10, characterized in that the liquid connections (12) are arrangedstationarily one behind the other relative to the path of movement (B),whereby the objects (29) can be moved preferably on a transport path, inparticular a roller path, under the liquid connections (12).
 13. Thedevice according to claim 10, characterized in that the valves (17) ofthe nozzles (24) can be controlled, in particular individually, in orderto achieve a specific surface distribution (26) of the discharge ofliquid over the path of movement (B).
 14. The device according to claim10, characterized in that the nozzles (24) are arranged on the liquidconnection (12) with a small distance therefrom, whereby the valve (17)is arranged preferably between nozzle (24) and liquid connection (12).15. The device according to claim 10, characterized in that the nozzles(24) can be moved or changed in their alignment, whereby the nozzles(24) can preferably be changed individually or in groups, and inparticular the groups are divided in accordance with liquid connections(12).